Conventional electrical testers usually comprise electrical contacts such as contact probes, and an insulation socket cooperating with the contact probes. Devices under test (“DUT”) are placed onto the insulation socket and the contact probes make electrical contact with the DUT mounted on the insulation socket during testing.
FIG. 1 is an isometric view of a conventional rotary turret disk 100 having multiple test stands 102. There are a total of sixteen test stands 102 installed in the illustrated rotary turret disk 100. The test stands 102 are positioned along a perimeter of the rotary turret disk 100, and are equally spaced from one another. Each test stand 102 has an insulation socket 104 positioned on top of it surface for mounting a DUT for testing.
Pick arms are generally used for transferring the DUT to the insulation socket 104 and to remove the DUT after testing. The position of a test contactor module is generally fixed and the contact probes of the test contactor module are used to make the necessary electrical contact for electrically testing the DUT. Thus, the rotary turret disk 100 rotates incrementally to position each test stand 102 and insulation socket 104 at a position of the test contactor module in order to conduct electrical tests on the DUT.
For production of LED devices in particular, electrical tests have to be performed on the LEDs, and the performance of the contact probes will affect the test results. Amongst the tests carried out, a forward voltage test requires the contact probes to have very good electrical conductivity, otherwise a large variation in the forward voltage or Vf range and unreliable production test yields will result. In order to overcome this, an operator has to monitor the test results and clean the contact probes manually either periodically to ensure good performance, or whenever necessary if test results are unsatisfactory.
In common practice, the contact probes need to be manually cleaned to retain good conductivity of the contact probes to remove contaminants, whether after long machine stoppage or bad contact, or under abnormal testing conditions such as Vf measurement fluctuation, and so on. This requires the testing machine's operations to be halted and leads to downtime. It is very time-consuming and wastes manpower.